More Conditionals and Loops - Java Software Solutions: Foundations of Program Design - page 273

LISTING 6.1 continued

case 7:
System.out.println ("average.");
break ;
case 6:
System.out.println ("below average. You should see the");
System.out.println ("instructor to clarify the material "
+ "presented in class.");
break ;
default :
System.out.println ("not passing.");
}
}
}

OUTPUT

Enter a numeric grade (0 to 100): 86
That grade is above average. Nice job.

In GradeReport , the category of the grade is determined by dividing the grade
by 10 using integer division, resulting in an integer value between 0 and 10
(assuming a valid grade is entered). This result is used as the expression of the
switch , which prints various messages for grades 60 or higher and a default sen-
tence for all other values.
Note that any switch statement could be implemented as a set of nested if
statements. However, nested if statements quickly become difficult for a human
reader to understand and are error prone to implement and debug. But because a
switch can evaluate only equality, sometimes nested if statements are necessary.
It depends on the situation.

SELF-REVIEW QUESTIONS (see answers in Appendix N)
SR 6.1

When a Java program is running, what happens if the expression eval-
uated for a switch statement does not match any of the case values
associated with the statement?

SR 6.2 What happens if a case in a switch statement does not end with a

break statement?

SR 6.3 What is the output of the GradeReport program if the user enters

“72”? What if the user enters “46”? What if the user enters “123”?